Pyrolysis of carbonaceous materials with solvent quench recovery

Abstract

In a continuous process for recovery of values contained in a solid carbonaceous material, the carbonaceous material is comminuted and then subjected to flash pyrolysis in the presence of a particulate heat source to form a pyrolysis product stream containing a carbon containing solid residue and volatilized hydrocarbons. After the carbon containing solid residue is separated from the pyrolysis product stream, values are obtained by condensing volatilized hydrocarbons. The particulate source of heat is formed by oxidizing carbon in the solid residue. Apparatus useful for practicing this process are disclosed.

Description

Claims

1. A continuous process for recovery of values contained in solid carbonaceous materials which comprises the steps of:

a. providing a feed stream containing a particulate solid carbonaceous material, a substantial portion of the particulate solid carbonaceous material being of a particle size less than about 1000 microns in diameter;

b. subjecting the particulate solid carbonaceous material particles to flash pyrolysis by continuously:

(i) transporting the particulate solid carbonaceous material containing feed stream contained in a carrier gas which is substantially nondeleteriously reactive with respect to products of pyrolysis of the particulate solid carbonaceous material to a solids feed inlet of a substantially vertically oriented, descending flow pyrolysis reactor having a substantially vertically oriented pyrolysis zone operated at a pyrolysis temperature above about 600.degree. F;

(ii) feeding a particulate source of heat at a temperature above the pyrolysis zone temperature to a substantially vertically oriented chamber surrounding the upper portion of the pyrolysis reactor, the chamber having an inner peripheral wall forming an overflow weir to a vertically oriented mixing section of the vertically oriented descending flow pyrolysis reactor, the particulate heat source in said chamber being maintained in a fluidized state by the flow therewith of an aerating gas substantially nondeleteriously reactive with respect to products of pyrolysis of the particulate solid carbonaceous material;

(iii) discharging the particulate source of heat over said weir and downwardly into said mixing section at a rate sufficient to maintain said pyrolysis zone at the pyrolysis temperature;

(iv) injecting the particulate solid carbonaceous material feed stream and carrier gas from the solids feed inlet into the mixing section to form a resultant turbulent mixture of the particulate source of heat, the particulate solid carbonaceous material particles and carrier gas;

(v) passing the resultant turbulent mixture downwardly from said mixing section to the pyrolysis zone of said pyrolysis reactor to pyrolyze the solid carbonaceous material particles and yield a pyrolysis product stream containing as particulate solids, the particulate source of heat and a carbon containing solid residue of pyrolysis of the particulate solid carbonaceous material, and a vapor mixture of carrier gas and pyrolytic vapors comprising volatilized hydrocarbons including tars;

c. passing the pyrolysis product stream from said pyrolysis reactor to a separation zone to separate at least the bulk of the particulate solids from the vapor mixture;

d. forming the particulate source of heat by:

(i) transporting the separated particulate solids from the separation zone to an oxidation stage with a transport gas containing free oxygen with resultant carbon monoxide formation from reaction of oxygen in the transport gas with carbon in the particulate solids; and

(ii) combining the transported particulate solids, carbon monoxide and transport gas in the oxidation stage with a source of free oxygen in an amount at least equal to 50 mole percent of the carbon monoxide entering the oxidation stage, the total free oxygen in the transport gas and combined in the oxidation stage being sufficient to raise the solids to a temperature above the pyrolysis temperature and thus form a particulate source of heat;

e. passing the particulate source of heat and gases present in the oxidation stage from the oxidation stage to a cyclone separation zone comprising at least two cyclone separation stages in series to separate the bulk of the particulate source of heat from the gases in the first cyclone separation stage to form the feed to the substantially vertically oriented chamber and to separate a fines fraction of the particulate source of heat from the gases in the remaining cyclone separation stages; and

f. recovering tar and low boiling hydrocarbon values from the vapor mixture by the steps of:

(i) contacting the vapor mixture with a quench liquid consisting essentially of hydrocarbons, said quench liquid having a temperature sufficiently low to form a tar-containing condensate and a vapor residue from the vapor mixture, the condensate and quench liquid forming a combined liquid stream;

(ii) mixing a viscosity-lowering liquid comprising hydrocarbons with the combined liquid stream, thereby forming a mixed liquid, said viscosity-lowering liquid having a viscosity lower than the viscosity of said mixed liquid, and said mixed liquid having a viscosity lower than the viscosity of said combined liquid stream;

(iii) cooling a first portion of said mixed liquid to form said quench liquid for contacting the vapor mixture;

(iv) separating a second portion of said mixed liquid into at least a viscosity-lowering liquid for mixing with said combined liquid stream and a tar fraction having a higher volume average boiling point than the volume average boiling point of said viscosity-lowering liquid; and

(v) recovering said tar fraction.

2. A process as claimed in claim 1 in which the oxidation zone comprises a cyclone oxidation-separation zone.

3. A process as claimed in claim 1 in which the pyrolysis temperature is from about 600.degree. to about 2000.degree. F.

4. A process as claimed in claim 1 in which the pyrolysis temperature is from about 600.degree. to about 1400.degree. F.

5. A process as claimed in claim 1 in which the pyrolysis temperature is from about 900.degree. to about 1400.degree. F.

6. A process as claimed in claim 1 in which a substantial portion of the particulate solid carbonaceous material are particles in the range from about 10 to about 1000 microns in diameter.

7. A process as claimed in claim 1 in which the particulate solid carbonaceous material is an agglomerative coal and a substantial portion of the particulate solid carbonaceous material is of a particle size less than about 250 microns in diameter.

8. A process as claimed in claim 1 in which the particulate solid carbonaceous material is an agglomerative coal, and a substantial portion of the particulate solid carbonaceous material is of a particle size in the range from about 10 to about 250 microns in diameter.

9. A process as claimed in claim 1 in which the resultant turbulent mixture has a particulate solids content ranging from about 0.1 to about 10% by volume based on the total volume of the resultant turbulent mixture and a weight ratio of the particulate source of heat to particulate solid carbonaceous material of from about 2 to about 20:1.

10. A process as claimed in claim 1 having a pyrolysis time of less than about 5 seconds.

11. A process as claimed in claim 1 wherein the temperature of said mixed liquid is above about 100.degree. F and below 700.degree. F.

12. A process as claimed in claim 1 wherein the temperature of said mixed liquid is between about 200.degree. F and about 500.degree. F.

13. A process as claimed in claim 1 wherein the weight ratio of said viscosity-lowering liquid mixed with said combined liquid stream to said tar-containing condensate is from about 0.01 to about 500.

14. A process as claimed in claim 1 wherein the weight ratio of said viscosity-lowering liquid mixed with said combined liquid stream to said tar-containing condensate is from about 0.1 to about 100.

15. A process as claimed in claim 1 wherein said second portion of said mixed liquid is separated by distillation.

16. A process as claimed in claim 1 wherein said separating of said second portion is by distillation at less than atmospheric pressure.

17. A process as claimed in claim 1 comprising the additional step of recovering a portion of said viscosity-lowering liquid separated from said mixed liquid as an intermediate boiling hydrocarbon fraction.

18. A process as claimed in claim 1 comprising the additional step of cooling at least a portion of said viscosity-lowering liquid mixed with said combined liquid stream prior to mixing said viscosity-lowering liquid with said combined liquid stream.

19. A process as claimed in claim 1 comprising the additional step of treating said vapor residue to recover additional liquid product.

20. A continuous process for recovery of values contained in solid carbonaceous materials comprising the steps of:

a. providing a particulate solid carbonaceous material feed stream substantially containing particles of a size about 10 to about 1000 microns in diameter;

b. subjecting the particulate solid carbonaceous material particles to flash pyrolysis by continuously:

(i) transporting the particulate solid carbonaceous material feed stream contained in a carrier gas which is substantially nondeleteriously reactive with respect to products of pyrolysis of the particulate solid carbonaceous material to a solids feed inlet of a vertically oriented, descending flow pyrolysis reactor having a pyrolysis zone operated at a pyrolysis temperature of from about 600.degree. to about 2000.degree. F;

(ii) feeding a particulate source of heat at a temperature above the pyrolysis zone temperature to a vertically oriented chamber surrounding the upper portion of the pyrolysis reactor, the chamber having an inner peripheral wall forming an overflow weir to a vertically oriented mixing section of the vertically oriented descending flow pyrolysis reactor, the particulate heat source in said chamber being maintained in a fluidized state by the flow therewith of an aerating gas substantially nondeleteriously reactive with respect to the products of pyrolysis of the particulate solid carbonaceous material;

(iii) discharging the particulate source of heat over said weir and downwardly into said mixing section at a rate sufficient to maintain said pyrolysis zone at the pyrolysis temperature;

(iv) injecting the particulate solid carbonaceous material feed stream and carrier gas from the solids feed inlet into the mixing section to form a resultant turbulent mixture of said particulate source of heat, particulate solid carbonaceous material and carrier gas;

(v) passing the resultant turbulent mixture downwardly from said mixing section to the pyrolysis zone of said pyrolysis reactor to pyrolyze the particulate solid carbonaceous material and yield a pyrolysis product stream containing as particulate solids, the particulate source of heat and a carbon containing solid residue of pyrolysis of the particulate solid carbonaceous material, and a vapor mixture of carrier gas and pyrolytic vapors comprising volatilized hydrocarbons including tars, intermediate boiling hydrocarbons, and low boiling hydrocarbons, the pyrolysis time being less than about 5 seconds;

c. passing the pyrolysis product stream from said pyrolysis reactor to a cyclone separation zone to separate the bulk of the solids from the vapor mixture;

d. forming the particulate source of heat by:

(i) transporting the separated particulate solids from the cyclone separation zone to a cyclone oxidation-separation stage with a transport gas containing free oxygen with resultant carbon monoxide formation from reaction of oxygen in the transport gas with carbon in the particulate solids; and

(ii) combining the transported particulate solids, carbon monoxide and transport gas in the cyclone oxidation-separation stage with a source of free oxygen in an amount at least equal to 50 mole percent of the carbon monoxide entering the cyclone oxidation-separation stage, the total free oxygen in the transport gas and combined in the oxidation-separation stage being sufficient to raise the particulate solids to the temperature required for introduction to the vertically oriented chamber, while simultaneously separating the gaseous products of oxidation from the thus produced heated particulate source of heat, the residence time in said cyclone oxidation-separation stage being less than about 5 seconds;

e. recovering hydrocarbon values from the vapor mixture by:

(i) contacting the vapor mixture in a quench zone with a quench liquid which is a cooled liquid mixture consisting essentially of tars dissolved in intermediate boiling hydrocarbons condensed from the vapor mixture to form a tar containing condensate and a vapor residue from the vapor mixture, the condensate and quench liquid forming a combined liquid stream;

(ii) collecting the combined liquid stream in a collection section and forming a mixed liquid by mixing the combined liquid stream with from about 0.01 to about 500 pounds of a viscosity-lowering liquid comprising intermediate boiling hydrocarbons condensed from the vapor mixture per pound of the tar containing condensate in the combined liquid stream;

(iii) cooling and recycling a portion of the mixed liquid from the collection section to the condensation section as quench liquid;

(iv) recovering a tar fraction from at least a portion of the balance of the mixed liquid to yield a substantially tar free viscosity-lowering liquid;

(v) returning at least a portion of the substantially tar free viscosity-lowering liquid to the quench zone to mix with the combined liquid stream; and

(vi) recovering a low boiling hydrocarbon fraction from the vapor residue.

21. A process as claimed in claim 20 in which the pyrolysis temperature is from about 600.degree. to about 1400.degree. F.

22. A process as claimed in claim 20 in which the particulate solid carbonaceous material is an agglomerative coal and the particulate solid carbonaceous material feed stream substantially contains particles of a size from about 10 to about 250 microns in diameter.

23. A process as claimed in claim 20 in which the resultant turbulent mixture has a particulate solids content ranging from about 0.1 to about 10% by volume based on the total volume of the resultant turbulent mixture and a weight ratio of the particulate source of heat to particulate solid carbonaceous material of from about 2 to about 20:1.

24. A process as claimed in claim 20 in which the pyrolysis temperature is from about 900.degree. to about 1400.degree. F.

25. A process as claimed in claim 20 in which the pyrolysis time is from about 0.1 to about 3 seconds.

26. A process as claimed in claim 20 in which the residence time in the cyclone oxidation-separation stage is from about 0.1 to about 3 seconds.

27. The process of claim 20 in which the step of recovering a tar fraction from mixed liquid comprises the step of distilling intermediate boiling hydrocarbons from the mixed liquid.

28. The process of claim 27 in which intermediate boiling hydrocarbons are distilled from the mixed liquid at less than atmospheric pressure.

29. A process as claimed in claim 20 in which the step of recovering a low boiling hydrocarbon fraction from the vapor residue comprises contacting the vapor residue with at least a cooled condensate of low boiling hydrocarbons condensed from the vapor mixture.

30. A continuous process for recovery of values contained in agglomerative coals which comprises the steps of:

a. producing a particulate agglomerative coal feed stream containing agglomerative coal particles of a size less than about 250 microns in diameter;

b. subjecting the particulate agglomerative coal feed stream to flash pyrolysis by continuously:

(i) transporting the particulate agglomerative coal feed stream and a carrier gas which is substantially nondeleteriously reactive with respect to the products of pyrolysis of the particulate agglomerative coal to the feed nozzle of a vertically oriented, descending flow pyrolysis reactor having a pyrolysis zone operated at a pyrolysis temperature from about 600 to about 2000.degree. F;

(ii) feeding a particulate source of heat at a temperature above the pyrolysis temperature, and comprising heated particulate carbon containing solid residue of pyrolysis of the particulate agglomerative coal, to a vertically oriented chamber surrounding the upper portion of the pyrolysis reactor, the chamber having an inner peripheral wall forming an overflow weir to a vertically oriented mixing section of the vertically oriented descending flow transport pyrolysis reactor, the particulate heat source in said chamber being maintained in a fluidized state by the flow therewith of an aerating gas substantially nondeleteriously reactive with respect to the products of pyrolysis of the particulate agglomerative coal feed;

(iii) discharging the particulate source of heat over said weir and downwardly into said mixing section at a rate sufficient to maintain said pyrolysis zone at the pyrolysis temperature;

(iv) injecting the particulate agglomerative coal feed stream and carrier gas from the feed nozzle into the mixing section to form a resultant turbulent mixture of said particulate source of heat, particulate agglomerative coal feed stream and carrier gas;

(v) passing the resultant turbulent mixture downwardly from said mixing section to the pyrolysis zone of said pyrolysis reactor to pyrolyze the particulate agglomerative coal feed stream and yield a pyrolysis product stream containing as particulate solids, the particulate source of heat and a particulate carbon containing solid residue of pyrolysis of the particulate agglomerative coal feed, and a vapor mixture of carrier gas and pyrolytic vapors comprising tars, intermediate boiling hydrocarbons, and low boiling hydrocarbons, the pyrolysis time being less than about 5 seconds;

c. passing the pyrolysis product stream from said pyrolysis reactor to a first cyclone separation zone comprising a plurality of cyclone separation stages to initially separate from the pyrolysis product stream the bulk of the particulate solids as coarse particulate solids in at least a first cyclone separation stage and to separate a fines fraction of the particulate solids from the vapor mixture in at least a second cyclone separation stage;

d. collecting the coarse particulate solids in a collection zone comprising a static bed of particulate solids;

e. compacting particulate solids from the static bed in a compaction stage for feed to a transport line;

f. transporting the particulate solids from the compaction zone to an oxidation stage with a transport gas containing free oxygen with resultant carbon monoxide formation from reaction of oxygen in the transport gas with carbon in the solids;

g. combining the particulate solids, carbon monoxide and transport gas in the oxidation stage with a source of free oxygen at least equal to 50 mole percent of the carbon monoxide entering the oxidation stage, the total free oxygen in the transport gas and combined in the oxidation stage being sufficient to raise the particulate solids to a temperature above the pyrolysis temperature and thus form a particulate source of heat;

h. passing the particulate source of heat and gases present in the oxidation stage from the oxidation stage to a cyclone separation zone comprising at least two cyclone separation stages in series to separate the bulk of the particulate source of heat from the gases in the first cyclone to form the feed to the vertically oriented chamber and to separate a fines fraction of the particulate source of heat from the gases in the remaining cyclone separation stages; and

i. recovering tar and low boiling hydrocarbon values from the vapor mixture by:

(i) contacting the vapor mixture with a quench liquid consisting essentially of tars and intermediate boiling hydrocarbons condensed from the vapor mixture to form a tar containing condensate and a vapor residue from the vapor mixture, the condensate and quench liquid forming a combined liquid stream;

(ii) mixing the combined liquid stream with a viscosity-lowering liquid comprising intermediate boiling hydrocarbons condensed from the vapor mixture to form a mixed liquid having a lower viscosity than the combined liquid stream;

(iii) cooling a portion of the mixed liquid to form the quench liquid for contacting the vapor mixture;

(iv) recovering the tar fraction from at least a portion of the balance of the mixed liquid to yield substantially tar free viscosity-lowering liquid for mixing with the combined liquid stream; and

(v) recovering a low boiling hydrocarbon fraction from the vapor residue.

31. A process as claimed in claim 30 in which the pyrolysis temperature is from about 900.degree. to about 1400.degree. F.

32. A process as claimed in claim 30 in which a substantial portion of the particulate agglomerative coal feed are particles in the range from about 10 to about 250 microns.

33. A process as claimed in claim 30 in which the resultant turbulent mixture has a particulate solids content ranging from about 0.1 to about 10% by volume based on the total volume of the resultant turbulent mixture and a weight ratio of the particulate source of heat to particulate agglomerative coal of from about 2 to about 20:1.

34. The process of claim 30 in which the step of recovering a tar fraction from the mixed liquid comprises the step of distilling intermediate boiling hydrocarbons from the mixed liquid.

35. A process as claimed in claim 30 in which the pyrolysis time is from about 0.1 to about 3 seconds.

36. A process as claimed in claim 30 in which the oxidation stage comprises a cyclone oxidation-separation stage.

37. A process as claimed in claim 36 in which the residence time in the cyclone oxidation-separation stage is from about 0.1 to about 3 seconds.

38. A continuous process for recovery of values contained in coals which comprises the steps of:

a. providing a particulate coal feed stream, a substantial portion of the particulate coal feed having a particle size from about 10 to about 1000 microns in diameter;

b. subjecting the particulate coal feed stream to flash pyrolysis by continuously:

(i) transporting the particulate coal feed stream and a carrier gas which is substantially nondeleteriously reactive with respect to the products of pyrolysis of the particulate coal feed to a solids feed inlet of a vertically oriented, descending flow pyrolysis reactor having a pyrolysis zone operated at a pyrolysis temperature from about 600 to about 2000.degree. F;

(ii) feeding a particulate source of heat at a temperature above the pyrolysis temperature, and comprising heated carbon containing solid residue of pyrolysis of the particulate coal feed, to a vertically oriented chamber surrounding the upper portion of the pyrolysis reactor, the chamber having an inner peripheral wall forming an overflow weir to a vertically oriented mixing region of the vertically oriented descending flow pyrolysis reactor, the particulate heat source in said chamber being maintained in a fluidized state by the flow therewith of an aerating gas substantially nondeleteriously reactive with respect to the products of pyrolysis of the particulate coal feed;

(iii) discharging the particulate source of heat over said weir and downwardly into said mixing region at a rate sufficient to maintain said pyrolysis zone at the pyrolysis temperature;

(iv) injecting the particulate coal feed stream and carrier gas from the solids feed inlet into the mixing region to form a resultant turbulent mixture of said particulate source of heat, particulate coal feed stream and carrier gas;

(v) passing the resultant turbulent mixture downwardly from said mixing region to the pyrolysis zone of said pyrolysis reactor to pyrolyze the particulate coal feed and yeild a pyrolysis product stream containing as particulate solids, the particulate source of heat and a carbon containing solid residue of pyrolysis of the particulate coal feed, and a vapor mixture of carrier gas and pyrolytic vapors comprising volatilized hydrocarbons including tars, intermediate boiling hydrocarbons, and low boiling hydrocarbons, the pyrolysis time being less than about 5 seconds;

c. passing the pyrolysis product stream from said pyrolysis reactor to a cyclone separation zone to separate the bulk of the particulate solids from the vapor mixture;

d. forming the particulate source of heat by:

(i) transporting the particulate solids from the cyclone separation zone to a cyclone oxidation-separation stage with a transport gas containing free oxygen with resultant formation of gaseous products including carbon monoxide from reaction of oxygen in the transport gas with carbon in the particulate solids; and

(ii) combining the particulate solids, carbon monoxide and transport gas in the cyclone oxidation-separation stage with a source of free oxygen in an amount at least equal to 50 mole percent of the carbon monoxide entering the cyclone oxidation-separation stage, the total free oxygen in the transport gas and combined in the cyclone oxidation-separation stage being sufficient to raise the particulate solids to a temperature above the pyrolysis temperature, while simultaneously separating the gaseous products of oxidation from the thus produced heated particulate source of heat, the residence time in said cyclone oxidation-separation stage being less than about 5 seconds;

e. recovering values from the vapor mixture by:

(i) quenching in a condensation section of a first quench stage which includes a liquid collection section, the vapor mixture to a temperature from about 100.degree. F to 700.degree. F with a quench liquid which is a cooled liquid mixture consisting essentially of tars dissolved in intermediate boiling hydrocarbons condensed from the vapor mixture to form a condensate containing tars and intermediate boilding hydrocarbon and a partially condensed vapor mixture; (ii) collecting the condensate containing tars and intermediate boiling hydrocarbons, and solids entrained in the vapor mixture in the liquid collection section of the first quench stage and forming a mixed liquid in said liquid collection section by mixing the condensate with a viscosity-lowering liquid comprising intermediate boiling hydrocarbons condensed from the vapor mixture, the mixed liquid having a lower viscosity than the condensate;

(iii) separating solids collected in the collection section from at least a portion of the mixed liquid;

(iv) cooling and recycling a portion of the mixed liquid from the collection section to the condensation section as quench liquid;

(v) recovering a tar fraction from at least a portion of the balance of the mixed liquid to yield a substantially tar free viscosity-lowering liquid by flash vaporizing at less than atmospheric pressure intermediate boiling hydrocarbons from the mixed liquid;

(vi) returning at least a portion of the substantially tar free viscosity-lowering liquid to the first quench stage to mix with and reduce the viscosity of the condensate;

(vii) contacting the partially condensed vapor mixture in a second quench stage with mixed liquid from the collection section of the first quench stage to form an intermediate boiling hydrocarbon condensate and a vapor residue; and

(viii) contacting the vapor residue with a cooled condensate from the vapor mixture to condense a low boiling hydrocarbon fraction from the vapor residue.

39. The process of claim 38 in which the vapor mixture is quenched to a temperature of above about 200.degree. F.

40. A process as claimed in claim 38 in the pyrolysis temperature is from about 600.degree. to about 1400.degree. F.

41. A process as claimed in claim 38 in which the pyrolysis temperature is from about 900.degree. to about 1400.degree. F.

42. A process as claimed in claim 38 in which the particulate coal feed is an agglomerative coal and a substantial portion of the particulate coal feed stream is of a particle size less than about 250 microns in diameter.

43. A process as claimed in claim 38 in which the particulate coal feed is an agglomerative coal, and a substantial portion of the particulate coal feed stream are particles in the range from about 10 to about 250 microns in diameter.

44. A continuous process for recovery of values contained in solid carbonaceous materials which comprises the steps of:

a. providing a feed stream containing a particulate solid carbonaceous material, a substantial portion of the particulate solid carbonaceous material being of a particle size less than about 1000 microns in diameter;

b. subjecting the particulate solid carbonaceous material to flash pyrolysis by continuously:

(i) transporting the particulate solid carbonaceous material feed stream contained in a carrier gas which is substantially nondeleteriously reactive with respect to the products of pyrolysis of the particulate solid carbonaceous material to a solids feed inlet of a substantially vertically oriented, descending flow pyrolysis reactor having a substantially vertically oriented pyrolysis zone operated at a pyrolysis temperature above about 600.degree. F;

(ii) feeding a particulate source of heat at a temperature above the pyrolysis temperature to a substantially vertically oriented chamber surrounding the upper portion of the pyrolysis reactor, the chamber having an inner peripheral wall forming an overflow weir to a vertically oriented mixing region of the vertically oriented descending flow pyrolysis reactor, the particulate source of heat in said chamber being maintained in a fluidized state by the flow therewith of an aerating gas substantially nondeleteriously reactive with respect to the products of pyrolysis of the particulate solid carbonaceous material;

(iii) discharging the particulate source of heat over said weir and downwardly into said mixing region at a rate sufficient to maintain said pyrolysis zone at the pyrolysis temperature;

(iv) injecting the particulate solid carbonaceous material feed stream and carrier gas from the solids feed inlet into the mixing region to form a resultant turbulent mixture of the particulate source of heat, the particulate solid carbonaceous material and the carrier gas;

(v) passing the resultant turbulent mixture downwardly from said mixing region to the pyrolysis zone of said pyrolysis reactor to pyrolyze the particulate solid carbonaceous material and yield a pyrolysis product stream containing as particulate solids, the particulate source of heat and a particulate carbon containing solid residue of pyrolysis of the particulate solid carbonaceous material, and a vapor mixture of carrier gas and pyrolytic vapors comprising volatilized hydrocarbons including tars;

c. passing the pyrolysis product stream from said pyrolysis reactor to a separation zone to separate at least the bulk of the particulate solids from the vapor mixture;

d. forming the particulate source of heat by subjecting carbon in the separated particulate solids to oxidation in an oxidation zone comprising at least one oxidation stage in the presence of an amount of free oxygen at least sufficient to raise the solids to a temperature above the pyrolysis temperature;

e. passing the thus produced particulate source of heat and gases present in the oxidation zone from the oxidation zone to a cyclone separation zone comprising at least two cyclone separation stages in series to separate the bulk of the particulate source of heat from the gases in the first cyclone separation stage to form the feed to the substantially vertically oriented chamber and to separate a fines fraction of the particulate source of heat from the gases in the remaining cyclone separation stages; and

f. recovering tar and low boiling hydrocarbon values from the vapor mixture by the steps of:

(i) contacting the vapor mixture with a quench liquid consisting essentially of hydrocarbons, said quench liquid having a temperature sufficiently low to form a tar-containing condensate and a vapor residue from the vapor mixture, the condensate and quench liquid forming a combined liquid stream;

(ii) mixing a viscosity-lowering liquid with the combined liquid stream, thereby forming a mixed liquid, said viscosity-lowering liquid having a viscosity lower than the viscosity of said mixed liquid, and said mixed liquid having a viscosity lower than the viscosity of said combined liquid stream;

(iii) cooling a first portion of said mixed liquid to form said quench liquid for contacting the vapor mixture;

(iv) separating a second portion of said mixed liquid into at least a viscosity-lowering liquid for mixing with said combined liquid stream and a tar fraction having a higher volume average boiling point than the volume average boiling point of said viscosity-lowering liquid; and

(v) recovering said tar fraction.

45. A process as claimed in claim 44 in which such an oxidation stage comprises a cyclone oxidation-separation stage.

46. A process as claimed in claim 44 in which the pyrolysis temperature is from about 600.degree. to about 2000.degree. F.

47. A process as claimed in claim 44 in which the pyrolysis temperature is from about 600.degree. to about 1400.degree. F.

48. A process as claimed in claim 44 in which the pyrolysis temperature is from about 900.degree. to about 1400.degree. F.

49. A process as claimed in claim 44 in which a substantial portion of the particulate solid carbonaceous material are particles in the range from about 10 to about 1000 microns in diameter.

50. A process as claimed in claim 44 in which the solid carbonaceous material is an agglomerative coal and a substantial portion of the particulate solid carbonaceous material is of a particle size less than about 250 microns in diameter.

51. A process as claimed in claim 44 in which the particulate solid carbonaceous material is an agglomerative coal, and a substantial portion of the particulate solid carbonaceous material is of a particle size in the range from about 10 to about 250 microns in diameter.

52. A process as claimed in claim 44 in which the resultant turbulent mixture has a solids content ranging from about 0.1 to about 10% by volume based on the total volume of the resultant turbulent mixture and a weight ratio of the particulate source of heat to solid carbonaceous material feed of from about 2 to about 20:1.

53. A process as claimed in claim 44 having a pyrolysis time of less than about 5 seconds.

54. A process as claimed in claim 44 wherein the temperature of said mixed liquid is above about 100.degree. F and below 700.degree. F.

55. A process as claimed in claim 44 wherein the temperature of said mixed liquid is between about 200.degree. F and about 500.degree. F.

56. A process as claimed in claim 44 wherein the weight ratio of said viscosity-lowering liquid mixed with said combined liquid stream to said tar-containing condensate is from about 0.01 to about 500.

57. A process as claimed in claim 44 wherein the weight ratio of said viscosity-lowering liquid mixed with said combined liquid stream to said tar-containing condensate is from about 0.1 to about 100.

58. A process as claimed in claim 44 wherein said second portion of said mixed liquid is separated by distillation.

59. A process as claimed in claim 44 wherein said separating of said second portion is by distillation at less than atmospheric pressure.

60. A process as claimed in claim 44 comprising the additional step of recovering a portion of said viscosity-lowering liquid separated from said mixed liquid as an intermediate boiling hydrocarbon fraction.

61. A process as claimed in claim 44 comprising the additional step of cooling at least a portion of said viscosity-lowering liquid mixed with said combined liquid stream prior to mixing said viscosity-lowering liquid with said combined liquid stream.

62. A process as claimed in claim 44 comprising the additional step of treating said vapor residue to recover additional liquid product.

63. A process as claimed in claim 44 further comprising treating said first portion of said mixed liquid with hydrogen.

64. A process as claimed in claim 44 further comprising treating said second portion of said mixed liquid with hydrogen.

65. A process as claimed in claim 44 wherein the vapor mixture contains entrained particulate solids, and wherein the mixed liquid contains such particulate solids, including the step of separating particulate solids from the mixed liquid.

66. A process as claimed in claim 65 including the step of recycling particulate solids separated from the mixed liquid to the pyrolysis reactor.

67. A process as claimed in claim 66 including the step of treating mixed liquid with hydrogen after separating particulate solids from the mixed liquid.

68. A process as claimed in claim 65, including the step of treating mixed liquid with hydrogen after separating particulate solids from the mixed liquid.

69. A process as claimed in claim 44 wherein the vapor mixture contains entrained particulate solids, and wherein the second portion of the mixed liquid contains such particulate solids, and including the step of separating particulate solids from the second portion of the mixed liquid.

70. A process as claimed in claim 69 including the step of recycling particulate solids separated from the second portion of the mixed liquid to the pyrolysis reactor.

71. A process as claimed in claim 44 further comprising treating said tar fraction with hydrogen.

72. A process as claimed in claim 44 further comprising treating said viscosity-lowering liquid with hydrogen prior to mixing said viscosity-lowering liquid with said combined liquid stream.

73. A process as claimed in claim 72 wherein the vapor mixture contains entrained particulate solids, and wherein the mixed liquid contains such particulate solids, including the step of separating particulate solids from the mixed liquid.

74. A process as claimed in claim 73 including the step of treating mixed liquid with hydrogen after separating particulate solids from the mixed liquid.

75. A process as claimed in claim 44 further comprising treating said mixed liquid with hydrogen.

76. A process as claimed in claim 75 where the vapor mixture contains entrained particulate solids, and wherein the mixed liquid contains such particulate solids including the step of separating particulate solids from at least a portion of the mixed liquid after treating said mixed liquid with hydrogen.

77. A process as claimed in claim 76 including the step of recycling particulate solids separated from the mixed liquid to the pyrolysis reactor.

78. A process as claimed in claim 72 including the step of holding mixed liquid at an elevated temperature for transferring hydrogen from viscosity-lowering liquid to condensate formed from the hydrocarbon-containing vapors.